Movements of cells include contraction, migration, release, aggregation and the like, and phosphorylation of the myosin regulatory light chain is important for these cell movements. The myosin regulatory light chain is a subunit having a molecular weight of 20 kDa and constituting myosin, which exists in smooth muscle cells and various non-muscle cells such as neutrophils, leukocytes, platelets and nerve cells of warm-blooded animals (Barany, K., et al., Biochemistry of Smooth Muscle Contraction, pp. 21–35, 1996). Myosin existing in smooth muscle cells and various non-muscle cells such as neutrophils, leukocytes, platelets and nerve cells of warm-blooded animals is constituted by a myosin heavy chain subunit having a molecular weight of about 200 kDa, the myosin regulatory light chain subunit having a molecular weight of about 20 kDa, and a myosin constitutive light chain subunit having a molecular weight of about 17 kDa. The myosin regulatory light chain is mainly phosphorylated by the myosin light chain kinase to increase the activity of myosin ATPase existing in the myosin heavy chain subunit (Barany, M., et al., Biochemistry of Smooth Muscle Contraction, pp. 321–339, 1996). It is known that the activated myosin having the increased ATPase activity becomes possible to interact with actin and activates movement apparatuses of cytoskeleton to activate cell movements. That is, it is known that activation of myosin relates to cell contraction (Kamm, K., et al., Annu. Rev. Physiol., 51, pp. 299–313, 1989). It is also known that activation of myosin relates to change of cell morphology (Schmidt, J. T. et al., J, Neurobiol., 52 (3), pp. 175–188, 2002). It is known that activation of myosin relates to cell migration (Niggli, V., FEBS Lett., 445, pp. 69–72, 1999). Further, it is known that activation of myosin relates to cell release (Kitani, S., et al., Biochem. Biophys. Res. Commun., 183, pp. 48–54, 1992). It is further known that activation of myosin relates to cell aggregation (Itoh, K., et al., Biochim. Biophys. Acta., 1136, pp. 52–56, 1992). It is also known that activation of myosin relates to cell apoptosis (Mills, J. C. et al., J. Cell Biol., Vol. 140, No. 3, pp. 627–636, 1998). Based on these findings, it is considered that an agent which inhibits the phosphorylation of the myosin regulatory light chain suppresses cell contraction, regulates change of cell morphology, suppresses cell migration, suppresses cell release, suppresses cell aggregation and suppresses cell apoptosis.
Cell contraction is deeply involved in diseases relating to contraction of various smooth muscle layers. Examples of such diseases include, for example, hypertension (Samlyo, A. P., et al., Rev. Physiol. Biochem. Pharmacol., Vol. 134, pp. 209–34, 1999), angina pectoris (Shimokawa et al., Cardiovasc. Res., Vol. 43, No. 4, pp. 1029–39, 1999; Satoh, H., et al., Jpn. J. Pharmacol., 79 (suppl.), p. 211, 1999), cerebral vascular spasm (M. Satoh et al., the 57th General Meeting of Japan Neurosurgical Society, Collection of Abstracts, 153, 1998; N. Ono et al., Pharmacol. Ther., Vol. 82, No. 2–3, pp. 123–31, 1991; Shimokawa et al., Cardiovasc. Res., Vol. 43, No. 4, pp. 1029–39, 1999), erectile dysfunction (Andersson, K E. et al., World J. Vrol., 15, pp. 14–20, 1997), bronchial asthma (K. Iidzuka, Allergy, 47, 943, 1998; K. Iidzuka et al., Jpn. J. Respirology Society, 37, 196, 1999) and the like.
Change of cell morphology is deeply involved in diseases relating to morphological change of various cells. Examples of the diseases relating to change of cell morphology include, for example, various nerve dysfunctions as those relating to nerve cells. As the nerve dysfunctions, for example, neural damages caused by trauma, neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, diabetic retinopathy, glaucoma and the like can be exemplified (Arakawa, Y., et al., BIO Clinica, 17 (13), pp. 26–28, 2002). Further, cell migration is deeply involved in diseases relating to migration of various cells. Examples of such diseases include, for example, cancer invasion and metastasis (Itoh, K. et al., Nat. Med., Vol. 5, No. 2, pp. 221–5, 1999; Keely, P. et al., Trends Cell Biol., Vol. 8, No. 3, pp. 101–6, 1998), nephritis (Fujimoto, O. et al., Journal of Japanese Society of Internal Medicine, 88 (1), pp. 148–58, 1998) and the like.
Furthermore, it is considered that cell release is deeply involved in various allergies and the like (Keane-Myers A. et al., Curr. Allergy Asthma Rep., 1(6):550–557, 2001), and further, cell aggregation is considered to be deeply involved in thrombosis and the like (Nakai, K. et al., Blood, Vol. 90, No. 10, pp. 3736–42., 1997). Further, it is known that cell apoptosis is involved in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and glaucoma, viral diseases, hepatic diseases and the like (Thompson, C. B., Science, Vol. 267, pp. 1456–1462, 1995).
Based on these findings, it is considered that the inhibitor of the phosphorylation of myosin regulatory light chain of the present invention, which is an agent inhibiting the phosphorylation of the myosin regulatory light chain, is useful as an active ingredient of a medicament for prophylactic and/or therapeutic treatment of a disease relating to cell contraction, disease relating to change of cell morphology, disease relating to cell migration, disease relating to cell release, disease relating to cell aggregation, and/or disease relating to cell apoptosis.
It has been reported that 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), which is an isoquinoline derivative, inhibits phosphorylation of the myosin regulatory light chain of mesenteric artery (Suzuki, A. et al., Br. J. Pharmacol., 109, pp. 703–712, 1993), iris smooth muscle (Howe, P. H. et al., Biochem J., 255, pp. 423–429, 1988), and astrocyte (Mobley P. L., et al., Exp. Cell Res., 214, pp. 55–66, 1994).